Hydraulic torque transmitting device and method of manufacture



July 5, 1955 v, J, JANDASE 2,712,285

HYDRAULIC TORQUE TRANSMIT I EVICE AND M HOD OF MANUFACTU ed July 5, 1952 I F/G. 2

V. J. JANDASEK INVENTOR.

B ,Mb

ATTOPNEVS United States Patent HYDRAULIC TORQUE TRANSMHTING DEVICE AND METHGD OF MANUFACTURE Application July 3, 1952, Serial No. 297,149

1 Claim. (Cl. 103-115) This invention relates generally to hydraulic torque transmitting devices.

The invention is primarily directed to the manner of attaching a shroud to the blades of a vaned element of a hydraulic torque transmitting device such as a fluid coupling or a torque converter. An object is to provide a hydraulic torque transmitting device of this type which lends itself to relatively simple fabrication and assembly so as to be suitable for mass production, and which in addition is capable of attaining the requisite etficiency and operating performance characteristics.

In one form of the invention, the outer shroud and the blades are cast in one piece with integral tabs projecting from the free edges of the blades. The tabs are machined so as to provide an undercuton each tab, and the inner shroud is formed of sheet metal with a plurality of slots positioned so as to receive the tabs on the blades. Adjacent each slot a tongue is sheared out of the inner shroud and is bent radially inwardly away from the blades so as to facilitate the assembly of the inner shroud to the tabs. After this assembly is completed, the tongues are rolled or otherwise bent into position adjacent the blades and in engagement with the adjacent edges of the tabs so as to retain the shroud permanently upon the blades. The invention is, of course, also applicable to sheet metal blades as well as cast blades.

Other objects and advantages of the invention will be made more apparent as this description proceeds, particular'ly when considered in connection with the accompanying drawings, in which:

Figure 1 is a cross-sectional view of the impeller of a torque converter embodying the present invention.

Figure 2 is a cross-sectional view taken on the plane indicated by the line 2-2 of Figure 1.

Figure 3 is an enlarged cross-sectional view, partly in elevation, on the line 33 of Figure 1.

Figure 4 is an enlarged cross-sectional view of a portion of the blade and tab shown in Figure 1 as initially cast.

Figure 5 is a cross-sectional view similar to Figure 4 but showing the blade and tab after machining and with the shroud as initially assembled thereto.

Figure 6 is a cross-sectional view similar to Figure 5 but showing the completed assembly after the tongues on the shroud have been rolled into interlocking engagement with the tabs.

Figure 7 is a cross-sectional view similar to Figure 6 but showing a modification thereof.

Although the present invention is applicable to fluid couplings, torque converters, and other types of hydraulic torque transmitting devices, and is applicable to the various vaned elements of such devices, for the purposes of illustration the invention is shown in connection with the impeller of the hydraulic torque converter of the type suitable for automotive use. As shown inthe drawing, and particularly in Figure 1, the impeller 11 is provided with a flange 12 for suitable connection to a driving member, a shroud portion 13, and an inner flange 14 arranged undercut edges of the tabs effectively to be connected to the adjacent flange 16 of a hub member 17 by means of bolts 18. Integrally cast in one piecewith the impeller shroud 13 are a plurality of blades 19. In the particular instance shown the shroud 13 and blades 19 are so designed that the casting can be made with a straight draw requiring only a single core for all of the blades. The casting may be a die casting or made by other suitable casting processes.

Integrally cast with each blade 19 of the impeller is a tab 21. With reference now to Figure 4, the tab 21 as initially formed projects radially inwardly from the inner peripheral edge 20 of the blade 19. The radially outer edge 22 of the tab is formed substantially at right angles to the inner edge 20 of the blade, but the radially inner edge 23 of the tab extends substantially axially of the impeller so as to enable the casting to be made with a straight draw. 7

The next step in the fabrication of the impeller assembly is to machine the radially inner edge 23 of the tab 21 so as to provide an undercut edge 24 as shown in Figure 5. The machined inner edge 24 of the tab may be substantially parallel to the outer edge 22.

An annular sheet metal inner shroud 26 is provided for attachment to the blades 19 of the impeller. As best seen in Figure 3, the inner shroud 26 is formed with an elongated slot 27 for each tab 21 so located as to receive the tab. Adjacent each elongated slot 27 is a tongue 28 struck from the inner shroud 26 and projecting radially inwardly therefrom toward the axis of the shroud. The initial position of the tongue 28 is best seen in Figure 5, and it will be noted that the tongue has a central bowed portion 29,and a terminal end portion 31 with the end portion located radially inwardly of the tab 21. This enables the shroud to be assembled to the blades 19 simply by moving the annular inner shroud axially toward the blades. It will benoted from Figure 3 that a slight clearance is provided between the slot 27 and the tab 21 so that the assembly of the inner shroud to the blades may be readily made even though slight manufacturing variations may exist.

After the inner shroud is positioned on the impeller with the tabs 21 of the impeller blades projecting through the slots 27 in the shroud, the tongues 28 on the shroud are rolled radially outwardly from the position shown in Figure 5 to that shown in Figure 6. This rolling operation bends the tongues 29 radially outwardly away from the axis of the inner shroud against the inner edges 20 of the blades 19 of the impeller and in addition flattens the bowed portions 29 of the tongues sufficiently to project the terminal ends 31 of the tongues into engagement with the inner edges 24 of the tabs. It will be apparent that the inner shroud is now permanently retained in assembled relation with the blades, the engagement between the terminal ends of the tongues and the preventing displacement of the shroud from the blades.

Reference is now made to Figure 7 for a modification of the invention. In this construction, the blade 33 is formed with an integral tab 34. As initially cast, the tab 34 on the blade 33 is similar to the tab 21 on the blade 19 as shown in Figure 4. In machining the inner edge of the tab 34, however, the radially inner edge 36 of the tab is undercut to a greater extent than in the form of the invention shown in Figures 1 to 6. In fact, the inner edge 36 is undercut beyond a line 37 parallel to the radially outer edge 38 of the tab.

In the modification of Figure 7, the inner shroud 39 is, in its initial position, similar to the inner shroud 28 as shown in Figure 5. During the subsequent rolling operation, however, after the shroud has been initially assembled with the blades, the end portion 41 of the tongue 42 adjacent each tab 34 is bent to the position shown in Figure 7 in which the tongue lies against the adjacent edge of the blade and the terminal end of the tongue engages the undercut inner edge 36 of the tab.

Although the forms of the invention shown and described herein are directed to a vaned element comprising an outer shroud and blades integrally cast in one piece, the invention is applicable to other types of construction as well. For example, the structure can be used in connection with stamped blades in lieu of cast blades, and the undercut inner edge of the tabs could be formed as the blades are stamped. In addition, the invention could be applied to the outer shrouds of vaned elements of hydraulic torque transmitting devices as well as to the inner shrouds thereof. Depending upon the shape of the shroud, and the location of the tab, the tongues may be located either radially inwardly or outwardly of the tabs. Furthermore, although radial blades are shown in the drawing, the invention can be used in connection with blades of other shape, location or contour, and the tabs on the blades may also be nonradial. type the shroud could be assembled to the blades with a rotative as well as axial movement. Thus, several arrangements are possible, but it will be noted that in each the deformable tongues in their initial positions provide sufiicient clearance so that the shroud may be readily assembled to the blades with the tabs projecting through the corresponding slots in the shroud.

It will be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claim.

What is claimed is:

A vaned wheel for a hydraulic torque transmitting device comprising an annular outer shroud and a plurality of generally radially extending circumferentially spaced blades, each of said blades having a curved generally semi-circular inner edge with the semi-circular edge fac- With tabs of this ing away from the blade in a direction parallel to the axis of the outer shroud, each of said blades having an integral generally rectangularly shaped tab projecting toward the axis of the outer shroud from the radially outer portion of the generally semi-circular inner edge of the blade, the radially inner edge of each tab being inclined at an angle less than 45 to the axis of said outer shroud and the side edges of said tab being generally at right angles to said inner edge, and an annular sheet metal inner shroud generally semi-circular in cross section to conform to the generally semi-circular edge of each of said blades, said annular shroud having a plurality of elongated slots formed therein corresponding in size and location to the tabs projecting from said blades, and said annular inner shroud also having a deformable tongue struck out from said inner shroud in alignment with each of said slots and at the side of each of said slots closest the axis of said inner shroud, the end of each of said deformable tongues being spaced radially inwardly of the radially inner edge of each of said tabs to provide clearance for the assembly of said inner shroud to said blades by movement of said inner shroud in an axial direction toward said blades to project said tabs through the slots in said inner shroud, said tongues being deformable to permit radially outward movement thereof into overlapping and interlocking engagement with the adjacent end of the tabs to prevent disengagement of said inner shroud from said blades.

References (Iited in the file of this patent UNTTED STATES PATENTS 

